a term used to describe something that is retarded. (backwards, overly excited, challenged, dimwitted, etc.)
the term is used to highlight how little of a idea makes sense, or how little of ones brain someone at a particular instant was using.
politically incorrect either way: this term was originally coined for our disabled public, but is now used in a more common slang manner.
"the dog went totally 7% when I got home last night!"
"you are about up to 7% with that grand idea."
"are you 7%, or what?"
"that's the most 7% thing i've heard all day."
"you have about a 7% chance of making that work."